Telescopic jib and bearing means therefor

ABSTRACT

A mobile crane comprises a multisection telescopic boom and an optionally usable multisection telescopic lattice type jib (having a base section and axially movable intermediate and fly sections) which when not in use is telescoped and stored on a support in parallel reverse disposition alongside the boom. Each jib section comprises four hollow tubular longitudinal members (each of rectangular cross section) arranged in parallel spaced apart relationship with a plurality of angularly disposed tubular cross braces connected between each pair of members to define a jib section of rectangular cross section. Each longitudinal member is rotated on its axis to present opposite inwardly and outwardly facing flat bearing surfaces and also to present two other opposite flat surfaces to which the ends of the cross braces are welded. Bearing means are provided to facilitate relative sliding motion and to transmit thrust forces between adjacent jib sections. The bearing means comprises inwardly facing slide pads mounted at the lower front ends of the base and intermediate sections and outwardly facing slide pads mounted at the upper and lower rear ends of the intermediate and fly sections; each slide pad being mounted on a support secured within the hollow end of a tubular longitudinal member and engaged with an appropriate bearing surface on an adjacent jib section. To unstore the jib and set it up for use, the foot end of the jib is releasably connected by pivot pin means to the point end of the boom and the boom is partially extended to axially move the jib forward clear of its support. At this stage the unextended jib may be swung 180* about the pivot pin means into axial alignment with the boom and rigidly secured thereto by suitable attachment means. Or, the jib may be partially or fully extended prior to being swung 180* by connecting either the jib intermediate section or the jib fly section, respectively, by releasable rear pin means to the boom base section and by then further extending the boom, either partially or fully, respectively. In all cases, prior to swinging the jib, a guy wire jib mast pivotally attached to the boom point and folded back alongside the boom is swung into upright position. The jib is designed so that it can be rigidly connected at an angle to the boom axis and so that the jib fly section can be rigidly connected at an angle to the jib axis.

Primary Examiner-Robert B. Reeves Assistant ExaminerHadd Lane Attorney, Agent, or Firm-James E. Nilles [57] ABSTRACT A mobile crane comprises a multisection telescopic boom and an optionally usable multisection telescopic lattice type jib (having a base section and axially movable intermediate and fly sections) which when not in use is telescoped and stored on a support in parallel reverse disposition alongside the boom. Each jib section comprises four hollow tubular longitudinal members (each of rectangular cross section) arranged in parallel spaced apart relationship with a plurality of angularly disposed tubular cross braces connected be- O United States Patent [191 [111 3,830,376 Fritsch Aug. 20, 1974 [5 TELESCOPIC JIB AND BEARING MEANS tween each pair of members to define a jib section of THEREFOR rectangular cross section. Each longitudinal member is rotated on its axis to present opposite inwardly and [75] Inventor a l? Fmsch Cedar Raplds outwardly facing flat bearing surfaces and also to present two other opposite flat surfaces to which the ends [73] Assignee: Harnischfeger Corporation, of the cross braces are welded. Bearing means are pro- Milwaukee, Wis. vided to facilitate relative sliding motion and to trans- [22] Filed: Feb. 16, 1973 mit thrust forces between ad acent JIb SeCIIC mS. The bearing means comprises inwardly facing slide pads [21] Appl. No.: 333,376 mounted at the lower front ends of the base and intermediate sections and outwardly facing slide pads mounted at the upper and lower rear ends of the inter- [52] US. Cl. 212/144, 212/55 mediate and fly Sections; each Slide pad being [51] Int. Cl. B66c 23/62 [58] Field of Search 212/l44 55 52 53 mounted on a support secured within the hollow end of a tubular longitudinal member and engaged with an appropriate bearing surface on an adjacent jib section. [56] References Cited To unstore the jib and set it up for use, the foot end of UNITED STATES PATENTS the jib is releasably connected by pivot pin means to 2,684,159 7/1954 Oldenkamp 212/55 the pomt end of the boom and the boom 15 part ally 3,029,954 4/1962 1 i 212/55 extended to axially move the jib forward clear of its 3,082,881 4/1963 W eger 212/55 Support At this Stage the unextended jib may be 3,610,433 10/1971 Milner, Jr. 212/144 X swung 180 about the pivot pin means into axial alignment with the boom and rigidly secured thereto by suitable attachment means. Or, the jib may be partially or fully extended prior to being swung 180 by connecting either the jib intermediate section or the jib fly section, respectively, by releasable rear pin means to the boom base section and by then further extending the boom, either partially or fully, respec tively. In all cases, prior to swinging the jib, a guy wire jib mast pivotally attached to the boom point and folded back alongside the boom is swung into upright position. The jib is designed so that it can be rigidly connected at an angle to the boom axis and so that the jib fly section can be rigidly connected at an angle to the jib axis.

15 Claims, 24 Drawing Figures PAIENIED AUGZOISM SHEET 2 OF 9 PATENTEU 3,830,376

SHEET 30F 9 m 00w oOw 8 @w ww m E 4 h M 9 "#0 JS m na V A/ x g mm x% E1 0% 08 8. g 5 E Q m 0E mm cow 0% ow /4 mm 8. XXXXXXXXXXXXX w/ o? w fi/ 92 mm 1 mm 5 5 08 08 S 8 NE E Q? w Jo mo N cow 00w w mm I: l M u m? wm w/ R 0 HQ V, o9 Ow :1 I I5 q f H z mm mm 2 O8 08 mm 8 ms TELESCOPIC JIB AND BEARING MEANS THEREFOR BACKGROUND OF THE INVENTION 1. Field of Use This invention relates generally to cranes, such as mobile cranes, having a multisection telescopic boom and an optionally usable multisection telescopic jib, such as a lattice type jib, for use with the boom.

In particular it relates to improved jibs of the aforesaid character, to improved jib sections therein, and to improved bearing means between adjacent jib sections to facilitate relative movement and distribute thrust forces therebetween.

The invention is particularly well-adapted for use in a crane such as disclosed in copending U.S. Pat. application Ser. No. 333,377, filed Feb. 16, 1973 for Mobile Crane With Telescopic Boom and Jib and Method for Connecting the Latter" filed by Daniel C. Wiencek and assigned to the same assignee as the present application.

2. Description of the Prior Art In telescopic jibs and booms (hereinafter collectively referred to as jibs) such as are used on mobile cranes or other equipment, it is usually necessary to provide bearing means, in the form of rollers or slide pads, between adjacent hollow telescopic jib sections to facilitate sliding movement therebetween and to assist in transmitting thrust forces from one jib section to another. U.S. Pats. No. 3,481,490; 2,648,149 and 3,082,881 disclose examples of jibs of this type employing such bearing means in the form of rollers. In U.S. Pat. No. 3,481,490, for example, a roller mounted on one slab-sides tubular jib section bears against and rides on a bevelled or chamfered surface provided at the corner of an adjacent slab-sided hollow jib section. In U.S. Pat. No. 2,684,159, a roller on one jib section cooperates with either the outer or inner surface of a tubular member forming part of the corner structure of an adjacent triangular slab-sided tubular jib section. In U.S. Pat. No. 3,082,881 rollers are used in a lattice type jib having sections of triangular cross section and are connected to the sides of the jib section.

As the size of cranes and jibs increases it is expeditious to employ extremely large lattice-type telescopic jibs because of their relatively greater strength-weight ratio. However, because of the type of structural members employed and because of the many cross brace members required in such jibs (resulting in the absence of broad flat slab-sided bearing surfaces) and the usual methods of manufacture employed (welding techniques which result in rough corner surfaces), it has heretofore been difficult to design and fabricate dependable, trouble free and economic large telescopic lattice type jibs and suitable bearing means for use between adjacent telescopic jib sections thereof.

SUMMARY OF THE PRESENT INVENTION A mobile crane comprises a multisection telescopic boom and an optionally usable multisection telescopic lattice type jib (having a base section and axially movable intermediate and fly sections) which when not in use is telescoped and stored on a support in parallel reverse disposition alongside the boom. To unstore the jib and set it up for use, the foot end of the jib is releasably connected by pivot pin means to the point end of 2, the boom and the boom is partially extended to axially move the jib forward clear of its support. At this stage the unextended jib may be swung about the pivot pin means into axial alignment with the boom and rigidly secured thereto by suitable attachment means. Or, the jib may be partially or fully extended prior to being swung 180 by connecting either the jib intermediate section or the jib fly section, respectively, by releasable rear pin means to the boom base section and by then further extending the, either partially or fully, respectively.

In accordance with the invention each jib section comprises four hollow tubular longitudinal members (each of rectangular cross section) arranged in parallel spaced apart relationship with a plurality of angularly disposed tubular cross braces connected between each pair of members to define a jib section of rectangular cross section. Each longitudinal member is rotated on its axis to present opposite inwardly and outwardly facing flat bearing surfaces and also to prevent two other opposite flat surfaces to which the ends of the cross braces are welded. Bearing means are provided to facilitate relative sliding motion and to transmit thrust forces between adjacent jib sections. In further accordance with the invention, the bearing means comprises inwardly facing slide pads mounted at the lower front ends of the base and intermediate sections and outwardly facing slide pads mounted at the upper and lower rear ends of the intermediate fly sections; each slide pad having an antifriction surface such as polyethylene being mounted on a support secured within the hollow end of a tubular longitudinal member and engaged with an appropriate bearing surface on an adjacent jib section. The jib is dsigned so that it can be rigidly connected at an angle to the boom axis and so that the jib fly section can be rigidly connected at an angle to the jib axis.

A jib in accordance with the present invention can be relatively large yet very strong and easily telescopable for use or storage because of the improved manner in which the jib sections are constructed and because of the improved construction of the bearing means employed therein. Furthermore, strong jib sections in accordance with the invention are relatively easy and economical to fabricate from strong, easily welded, standard-shaped sub-components, such as tubular steel. In addition, the improved bearing means in accordance with the invention are fabricated from readily available, simply-shaped non-critical commercially available sub-components, such as standard square steel stock, standard bolts, flat shims, and frictionreducing slide pads made of polyethylene or the like. Each slide pad and support is usable at any position where it may be required without the need for special adaptation. The slide pad supports are firmly secured in a positive non-rotatable manner to the boom sections. Modular components and dimensions, standard cuts and repetitive fabrication techniques are used throughout each jib section. Furthermore, each longitudinal member presents oppositely disposed flat surfaces, each of which is available as a bearing surface, depending on which jib section it is used in. Other objects and advantages of the invention will hereinafter appear.

DRAWINGS FIG. 1 is a side elevational view of a mobile crane having a multisection telescopic main boom and having a multisection telescopic jib disposed alongside the main boom in stored position according to the invention;

FIG. 2 is a top plan view of the mobile crane shown in FIG. 1;

FIG. 3 is a side elevational view, with portions broken away to conserve space, of a multi-section jib in accordance with the invention, showing the jib in fully extended condition;

FIG. 4 is an enlarged side elevational view of the jib base section shown in FIG. 3;

FIG. 5 is an enlarged side elevational view of the jib intermediate section shown in FIG. 3;

FIG. 6 is an enlarged side elevational view of the jib fly section shown in FIG. 3;

FIG. 7 is an enlarged cross sectional view taken on line 7-7 of FIG. 3;

FIG. 8 is an enlarged cross sectional view taken on line 88 of FIG. 3;

FIG. 9 is an enlarged top plan view representative of the front end of both the jib base and jib intermediate sections;

FIG. 10 is a side view of the jib section end shown in FIG. 9;

FIG. 11 is an end view of the jib section shown in FIG. 10;

, FIG. 12 is an enlarged top plan view representative of the rear end of both the jib intermediate and jib fly sections;

FIG. 13 is a side view of the jib section shown in FIG. 12;

FIG. 14 is an endview of the jib section shown in FIG. 13;

FIG. 15 is an enlarged cross sectional view of one of the slide pad supports and attached slide pad shown in FIG. 8;

FIG. 16 is a side view of the slide pad support and attached slide pad taken on line 16-16 of FIG. 15;

FIG. 17 is an isometric exploded view of the slide pad support and attached slide pad shown in FIGS. 15 and 16;

FIG. 18 is an enlarged top plan view of the point of the main boom and the foot end of the jib showing the foot end of the jib in fully connected position and also showing, in phantom, the jib folded alongside the main boom;

FIG. 19 is a side elevational view of the point of the main boom and the foot end of the jib, showing them in fully connected condition;

FIG. 20 is a top plan view of the main boom and the jib, shown schematically, wherein the main boom is fully retracted and the jib is fully retracted and stored alongside;

FIG. 21 is a view similar to FIG. 20 but showing one section 'of the main boom extended and showing the jib moved axially forward of its stored position;

FIG. 22 is a view similar to FIG. 20 wherein two sections of the main boom are shown extended and wherein one section of the jib is shown extended;

FIG. 23 is a view similar to FIG. 20 but showing all main boom sections extended and all jib sections extended, prior to swinging of the jib into final position; and

F [G 24 is a view similar to FIG. 20 but showing details of an alternative connection between one of the boom sections and one of the jib sections.

DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIGS. .1 and 2, there is shown apparatus 5 such as a mobile crane in accordance with the invention and which comprises a lower unit 10 in the form of a vehicle such as a truck and an upper unit 11 which is mounted for horizontal rotation in either direction on the lower unit by means of a conventional turret 17. Truck 10 comprises a chassis 12 on which are mounted ground wheels 13, extendable outriggers 14, a drivers cab 15 and an internal combustion engine 16 beneath the cab for driving the ground wheels. Upper unit 11 comprises a supporting framework 20 on which are mounted a telescopic boom B, main and auxiliary winches W1 and W2, respectively, on which load hoist lines MH and AH, respectively, are wrapped, a crane operators cab 21, and an internal combustion engine 22 for driving a hydraulic pump 23 which supplies operating fluid for the winches W1 and W2 and hydraulic cylinders hereinafter described.

Boom B, which is shown in a generally horizontal stored position lengthwise of truck 10, comprises four hollow boom sections, namely: a base section BI, an inner mid section BII, an outer mid section BIII, and a fly section BIV. Boom base section BI is pivotally connected to framework 20 of upper unit 11 by pin means 24. Extendable and retractable hydraulic boom hoist cylinders 25 are provided to raise and lower boom B and each is pivotally connected to and between framework 20 and boom base section BI by pin means 26 and 27, respectively. Fly section BIV is provided with a working head 34 at the boom point on which a sheave 35 for load hoist line MI-I is rotatably mounted.

A jib mast M is pivotally connected at one end by a pin 40 to working head 34 and is pivotable from a stored position alongside and beneath boom B, as shown in FIG. 1, to a raised position as shown in FIG. 3. Mast M is releasably secured in stored position by a bracket 41 attached to and beneath boom base section BI. In an actual embodiment, for example, boom B is fully extendable to about feet.

Extendable and retractable hydraulic boom extension cylinders 30, 31 and 32 are located within boom B and are connected to boom sections BII, Bill and BIV, respectively, to effect axial extension and retraction of the latter. Control means (not shown) are understood to be provided to operate the cylinders 30, 31 and 32 either individually or in unison, depending upon the crane operators choice.

A telescopic jib .I for optional use with boom B is shown in generally horizontal stored position on the crane alongside and parallel to the boom. Jib .I is stored at rest on jib storage means such as a roller 36 rotatably mounted on a bracket 37 which is shown attached to a side of base section B1 of boom B but which, for example, could be attached to and extend from, another component. Releasable jib locking means 94 are provided on bracket 37 to maintain telescoped jib J securely in place on its support during road transport. Preferably, additional locking means are provided for the point end of the stored jib and comprise a sidewardly projecting member 96 rigidly secured as by welding to the top of boom base section BI and to which the jib head is secured by bolt means 97. Jib J comprises three hollow lattice type jib sections, namely a jib base or foot section JI, a jib mid or intermediate section JII, and a jib fly or point section JIII. When jib J is fully telescoped and stored, as shown in FIGS. 1 and 2, it is reversely disposed with respect to boom B, i.e., its foot end is adjacent, near or toward the point of boom B and its point end is adjacent, near or toward the base of foot end of boom B. Jib fly section JIII is provided with a working head 43 at the jib point on which a sheave 44 for load hoist line AH is rotatably mounted. Jib J is adapted, for example, to extend the length of boom B by about 30, 50 or 70 feet, depending on how far it is extended for use.

As FIGS. 4 through show, each jib section JI, JII and JIII comprises, for example, four longitudinal parallel spaced apart tubular members 46, each of rectangular (preferably square) cross-sectional configuration, pairs of which are interconnected by short transversely (preferably at an angle of 60 as shown in FIGS. 4, 5 and 6) disposed hollow circular tubular members or cross braces 56 bevel cut at their ends and welded therebetween to define a jib section of rectangular cross section. Each longitudinal member 46 is rotated 45 on its axis (as shown in FIG. 15) to present opposite inwardly and outwardly facing flat bearing surfaces 45 and also to'present two other opposite flat surfaces 57 to which the ends of the cross braces 56 are welded, as at 568 in FIG. 15. Bearing means are provided to facilitate relative sliding motion and to transmit thrust forces between adjacent jib sections. The bearing means comprises inwardly facing slide pads 58 mounted at the lower front ends of the base section J I and intermediate section J [I and outwardly facing slide pads 58 mounted at the upper and lower rear ends of the intermediate section J II and fly section J III; each slide pad 58 being mounted by bolts 58A on a slide pad support 59 secured as by welding within the hollow end of a tubular longitudinal member 46 and engaged with an appropriate bearing surface 45 on an adjacent jib section.

As FIGS. 15, 16 and 17 show, a slide pad support 59 takes the form of a length of square steel bar stock having its corners chamfered as at 59A to adapt it to fit snugly within the substantially square hollow end of a longitudinal member 46 and having a relieved portion or surface as at 598. Support 59 is provided with two bolt holes 59C which extend therethrough from surface 593 to the opposite side and accommodate the bolts 58A which take into threaded holes 58C in slide pad 58 and secure slide pad in place. Shims 59D are disposed between relieved surface 598 and the bottom of slide pad 58 as required to maintain a proper fit or mating between slide pad 58 and the surface 45 on longitudinal member 46 against which it bears. Relieved portion or surface 598 enables a greater choice in the spacing or location of slide pad 58 with respect to surface 45.

To further strengthen and rigidify each slide pad support 59, each is connected to a supporting framework at the end of a jib section. Thus, as FIGS. 9, l0 and 11 show, the two slide pad supports 59 at the front end of jib base section J I (and also jib intermediate section J II) are connected as by welding at their outermost ends to a rectangular framework 100 formed of four lengths of angle iron. Only the lower two of the supports 59 carry inwardly facing slide pads 58. The framework 100, in turn, is secured as by welding to'four metal plates 10], each of which extends between and is welded to adjacent pairs of longitudinal members 46. As FIG. 10 shows, two of the plates 101 are side plates and each of these is provided with a pinning hole 48.

As FIGS. l2, l3 and 14 show, the four slide pad supports 59 at the rear end of jib intermediate section J II (and also jib fly section J III) are connected as by welding at their outermost ends to a rectangular framework formed of four lengths of square tubing. All four of these supports 59 carry outwardly facing slide pads 58. A cross brace 56A is connected to and between each support 59 and a longitudinal member 46. Additional transverse braces 56B are connected to and between oppositely disposed longitudinal members 46. Each smaller jib section is slidable or telescopable within the next larger jib section on the bearing means provided between the inner and outer surfaces of the longitudinal members 46 of adjacent jib sections.

As FIGS. 3, 4, 5 and 6 show, means are provided to secure the ends of adjacent jib sections together when the jib is fully extended and such means comprises suitable pinning plates rigidly secured as by welding to the sides of the jib sections at or near the forward end of jib section J I, to both ends of jib section J II, and to the rear end of jib section J III. The pinning plates are provided with pin holes such as 48 for receiving manually insertable and removable locking pins 49. More specifically, jib base section J I comprises pinning plates 47A and 478 near the front or forward end thereof, as FIG. 4 shows. Jib base section J I is also provided at the rear end thereof with connecting means hereinafter described in connection with FIGS. 18 and 19 which are adjustable to enable jib J to be mounted in axial alignment with boom B or angularly offset upwardly or downwardly with respect thereto, as hereinafter described. Jib intermediate section J II comprises pinning plates 47C, 47D and 47E near the front end thereof and with pinning plates 47F and 476 near the rear end thereof, as FIG. 5 shows. Jib fly section I III comprises pinning plates 47H, 471 and 47] near the front end thereof and with pinning plates 47K and 47L near the rear end thereof, as FIG. 6 shows. In addition, section J III is provided with an assembly 47, similar in construction to the assembly 60 at the foot end of jib base section J I hereinafter described in detail, which enables jib fly section J III to be used in axial alignment with jib J or angularly offset upwardly or downwardly with respect thereto.

As FIG. 3 shows, when jib J is fully extended, the plates 47K and 47L in section JIII are pinned to the plates 47C and 47D, respectively, of section JII. The plates 47F and 47G in section JII are pinned to the plates 47A and 473, respectively, of section Jl. When jib J is fully telescoped, as shown in FIGS. 1 and 2, other plates in the several sections come into alignment to enable the three boom sections to be securely pinned for storage and road transport purposes.

As FIGS. 1, 2, 3, 18 and 19 show, means are provided to connect the foot of jib J to the point of boom B so that, first, partial extension of the boom can effect forward axial movement of the jib from the position shown in FIG. 20 to a position clear of its support roller 36 as shown in FIG. 21; so that, second, further extension of the boom from the position shown in FIG. 21 can effect partial or full extension of the jib (see FIGS. 22 and 23, respectively); so that, third, the jib can be swung hori zontally into axial alignment with the boom, as FIG. 18 shows; and so that; fourth, the jib can be rigidly secured in axial alignment with the boom.

Thus, the working head 34 at the point end of boom fly section BIV is provided, on the lateral side thereof closestto jib J, with side mount pivot means 50. Pivot means 50 comprises a base plate 51 secured as bywelding to head 34, a supporting plate 52 secured as by welding to base plate 51 and extending transversely therefrom, a pair of supporting gussets 53 Welded between the plate 51 and the rear of plate 52, and a plurality of vertically arranged grouped pinning members 54 welded between plate 51 and the front of plate 52. Each pinning member 54 is provided with a pinning hole 55 therethrough and all such pinning holes are in vertical alignment or registry with each other. The pinning holes 55 in the top and bottom groups of pinning members 54 are adapted to receive vertically disposed removably insertable top and bottom pins P1, respectively, as FIGS. 18 and 19 show.

The foot end of jib base section J l is provided with a jib attachment assembly 60 comprising a base plate 61 rigidly secured as by welding to the base end of jib section J l and a boom attachmentplate 62. The plates 61 and 62 are each provided with a pair of triangularly shaped jib foot plates 63 and 64, respectively, which are secured thereto as by welding and extend transversely therefrom. The plates 63 and 64 are supported by gussets 65 welded between them and plates 61 and 62, respectively. Each plate 63 and its associated plate 64 overlap, as FIG. 19 shows, and each is provided with a hole 66 for receiving a jib foot pin 67. The base plate 6land the attachment plate 62 are also interconnected near'their corners by four offset links 68, each of which is pivotally interconnected to the plates 61 and 62 by offset link pins 69. The lengths of the offset links 68 de termine the relative planar disposition between the plates 61 and 62 and, therefore, determine whether the jib J will be in axial alignment with the boom B when connected thereto or whether the jib will be angularly offset upwardly or downwardly. In the embodiment shown, the offset links 68 are all of equal length and, therefore, the plates 61 and 62 are parallel and the axes of the jib J and the boom B would be in alignment with each other. Use of two top offset links of greater length than the two bottom offset links or vice versa, would result in the plates 61 and 62 being non-parallel and cause the jib J to be offset upwardly or downwardly when attached to boom B.

As FIG. 18 shows, the working head 34 at the point end of boom fly section BIV is provided on its lateral side farthest from stored jib J with side mount attachment means 70. Attachment means comprises a base plate 71 secured as by welding to head 34, a supporting plate 72 secured as by welding to plate 71 and extending transversely therefrom, a pair of supporting gussets 73 welded between the plate 71 and the rear of plate 72, and a plurality of vertically arranged grouped pinning members 74 welded between plate 71 and the front of plate 72. Each pinning member 74 is provided with a pinning hole 75 therethrough and all such pinning holes are in vertical alignment or registry with each other. The pinning holes 75 in the top and bottom groups of pinning members 74 are adapted to receive vertically disposed, removable insertable top and bottom pins P3, respectively, as FIG. 18 shows.

As FIGS. 18 and 19 show, the boom attachment plate 62 at the foot end of jib section J I is provided on its rear side with two groups of laterally projecting pinning members 80 and 81, each having a hole 83 therethrough, which are movable into cooperative relationship and alignment with pinning members 54 and 74,

respectively, on boom B, as hereinafter explained.

As FIGS. 2 and 20 through 24 show, boom base section BI is provided near its forward end on its lateral side closest to jib J with a pinning ear 85 having a hole 84 therein for receiving a removably insertable pin P2, shown in FIGS. 20 through 24. Pin P2 in used to secure pinning ear 85 either to a pinning car 86 on the fore end of jib section 1111 (for use in partial jib extension) or to a pinning car 87 in the fore end of jib section J III (for use in full jib extension). The ears 86 and 87 are provided with pinning holes 88 and 89, respectively.

As FIG. 3 shows, the jib sections J1 and JII are provided with stiff legs 90 and 91, respectively, which are shown in upright position and to which guy wires G are attached. Each stiff leg 90 and 91 is pivotally attached by a pin 92 to its respective jib section and is foldable downwardly to a stored position (or removable) when not in use.

OPERATION Assume that the crane is in the condition shown in FIGS. 1 and 2 with both the boom B and the jib] telescoped and stored, with all pins P1, P2 and P3 removed, and with jib J resting on the support roller 36 with the locking means 94 unlocked and locking bolt means 97 unsecured. To set up the jib, the pins P1 are manually inserted to connect the ears of jib base section J I to the ears 54 of boom fly section BIV. Boom cylinder 32 is then operated to extend boom fly section BIV and thereby effect forward axial movement of the entire telescoped jib J from the position shown in FIG. 20 to a position shown in FIG. 21 clear of its support roller 36.

At this point, the crane operator can choose to use the jib J in telescoped condition shown in FIG. 21, in partially extended condition shown in FIG. 22, or in fully extended condition shown in FIG. 23.

If the jib is to be used in fully telescoped condition as shown in FIG. 21, the jib mast M is swung into upright position and the jib is swung horizontally 180 about pin P1 until the holes 83 in the ears 81 on jib section J I align with the holes 75 in the ears 74 on boom fly section BIV, whereupon the pins P3 are inserted to lock the jib in position. Then, if necessary, the stiff leg 90 is raised or put in place, the guy line G is rigged thereto and the hoist line AH is reeved about sheave 44.

However, if the jib J is to be used in partially extended condition as shown in FIG. 22, the holes 84 and 88 in the ears and 86, respectively, are aligned by appropriate boom section movement and the pin P3 is inserted therethrough, as shown in FIG. 21, and the boom section B III is extended by operation of cylinder 31 to the position shown in FIG. 22 wherein the jib J is partially extended. Thereupon, pin P2 is removed and the jib J is swung horizontally 180 about pin P1 and the pin P3 is inserted, as hereinbefore explained. Prior to swinging jib J, the mast M must be erected. After the partially extended jib J is pinned in place, the stiff legs and 91 are erected and the guy line G and hoist line AH are rigged, as hereinbefore explained.

If the jib J is to be used in fully extended condition as shown in FIG. 23, the holes 84 and 89 in the ears 85 and 87, respectively, are aligned by appropriate boom section movment, as shown in FIG. 24, and the pin P2 is placed therethrough. Thereupon, the boom section Bill is extended by operation of cylinder 30 to the position shown in FIG. 23 wherein the jib J is fully extended. Thereupon, pin P2 is removed and the jib J is swung 180 into position (after swinging and placement of mast M) and the pin P3 is inserted, as hereinbefore explained. With the jib in place the stiff legs 90 and 91 are erected and the guy line G and hoist line Al-I are rigged, as hereinbefore explained.

After the jib J is in place and its sections properly secured by placement of the pins 49 in the holes 48, it can be. raised or lowered in accordance with the operation of boom B in the conventional manner.

To store the jib J after use, the boom B is lowered to horizontal position, the guy line G and hoist line AH are disconnected, the stiff legs 90 and 91 (if used) are folded down or removed, and the jib section pins 49 are removed (to permit jib section telescoping). The pins P3 are removed and the jib J is swung about pins P1 back alongside boom B. Thereupon, the appropriate jib section (either section J II or J 111) is connected to boom base section BI by pin P2, provided the jib is partially or fully extended, and the appropriate boom sections are retracted to fully telescope the jib sections. When jib J is fully telescoped, pin P2 is removed to detach the point end of the jib from boom base section BI, and cylinder 30 is operated to retract boom fly section B IV and thereby slide the jib back along the support roller 36 into stored position. Thereupon, the pins P1 are removed and jib J is secured in stored position. If desired, pins P1 may be left in place to prevent axial shifting of jib J during road trnasport, although such movement is also prevented by use of the jib locking means 95 provided on the jib support bracket 37 and the locking bolt 97 on bracket 96, as shown in FIGS. 1 and 2, which are understood to be releasably connectable to the jib.

In the embodiment disclosed, jib J is shown stored in reverse parallel relationship alongside one lateral side (the left side) of boom B. However, jib J can be stored on the other (right) side of boom B, if suitable provisions are made therefor in the construction and arrangement of various components, and such arrangements are within the scope of the present invention.

Also, when jib J is axially moved clear of its support roller 36, it may be swung 180 into and out of position either manually or by means of attachment of one of the hoist lines thereto and use of power from one of the winches.

Furthermore, although jib J is shown in FIG. 3 in axial alignment with boom B, jib J can be attached so as to be disposed at an angle with respect to boom B by appropriate setting or adjustment of the attachment means 60, i.e., by use of appropriately sized offset links. Similarly, jib fly section J IIl can be angled with respect to jib J after extension thereof by appropriate setting or adjustment of the attachment means 47 by appropriately sized offset links.

RESUME A mobile crane comprises a multisection telescopic boom B and an optionally usable multisection telescopic lattice type jib J (having a base section J I and axially movable intermediate and fly sections J II and J III, respectively,) which when no in use is telescoped and stored on a support roller 36 in parallel reverse disposition alongside the boom B. Each jib section comprises four hollow tubular longitudinal members 46 (each of rectangular cross section) arranged in parallel spaced apart relationship with a plurality of angularly disposed tubular cross braces 56 connected between each pair of members 46 to define a jib section of rectangular cross section. Each longitudinal member 46 is rotated 45 on its axis to present opposite inwardly and outwardly facing flat bearing surfaces 45 and also to present two other opposite flat surfaces 57 to which the ends of the cross braces 56 are welded. Bearing means are provided to facilitate relative sliding motion and to transmit thrust forces between adjacent relatively movable jib sections. The bearing means comprises inwardly facing slide pads 58 mounted at the lower front ends of the base and intermediate jib sections J I and J II, respectively, and outwardly facing slide pads 58 mounted at the upper and lower rear ends of the intermediate and fly jib sections J II and J III, respectively;

.each slide pad 58 being mounted on a suitably braced slide pad support 59 secured within the hollow end of a tubular longitudinal member 46 and engaged with an appropriate bearing surface 45 on an adjacent jib section. To unstore the jib J and set it up for use, the foot end of the jib is releasably connected by pivot pin means P1 to the point end of the boom B and the boom is partially extended to axially move the jib forward clear of its support 36. At this stage the unextended jib J may be swung about the pivot pin means P 1 into axial alignment with the boom B and rigidly secured thereto by suitable attachment means including pin means P3. Or, the jib J may be partially or fully extended prior to being swung 180 by connecting either the jib intermediate section J I] or the jib fly section J III, respectively, by releasable rear pin means P2 to the boom base section BI and by then further extending the boom, either partially or fully, respectively. In all cases, prior to swinging the jib J, a guy wire jib mast M pivotally attached to the boom point and folded back alongside the boom B is swung into upright position. The jib J is designed so that it can be rigidly connected at an angle to the boom axis by adjustment of attachment means 60 and so that the jib fly section J Ill can be rigidly connected at an angle to the jib axis by adjustment of attachment means 47.

I claim:

1. In apparatus having a telescopic jib; at least a pair of relatively telescopic jib sections, each section comprising four parallel spaced apart hollow tubular longitudinal members, each longitudinal member in each section having a rectangular cross section and comprising diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof and two flat surfaces to which the ends of cross braces are welded and having a bore of non-circular cross-sectional configuration, cross braces for joining each adjacent pair of Iongitudinal members and defining four planar sides of said jib sections, each longitudinal member being disposed on its axis so that all surfaces thereof are at a 45 angle with respect to the sides of its jib section, and two inwardly facing slide pad assemblies mounted at the lower front end of one section, two outwardly facing slide pad assemblies mounted at the lower rear end of the other section, and two outwardly facing slide pad assemblies mounted at the upper rear end of said other section, each slide pad assembly comprising a slide pad support of non-circular cross-sectional configuration inserted into and non-rotatably engaged within the bore at an end of one of said longitudinal members and a slide pad having a flat surface mounted on said slide pad support and slidably engaged with a flat bearing surface on a longitudinal member in an adjacent jib section. f

' '2; A jib according to claim 1 wherein said slide pad support is reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted.

3. In a telescopic jib: a base section, an intermediate section telescopable within said base section, and a fly section telescopable within said intermediate section; each of said sections comprising four parallel spaced apart hollow tubular longitudinal members, each of said longitudinal members having a rectangular cross section and comprising generally diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof and further comprising two other flat surfaces; a series of angularly disposed tubular cross braces for joining each adjacent pair of longitudinal members in'a section and defining sides of said section;

said cross braces being welded at each end to one of said. other flat surfaces of a longitudinal member; slide pad supports of rectangular cross section inserted into and now rotatably engaged within the ends of the longitudinal members at the front end of said base section, at both ends of said intermediate section, and at the rear end of said fly section; and flat slide pads mounted on the slide pad supports at the lower front end of said base section, at the upper and lower rear end of said intermediate section, at the lower front end of said intermediate section, and at the upper and lower rear end of said fly section, those slide pads at the lower front ends of said base section and said intermediate section being inwardly facing and all other slide pads being outwardly facing.

4. A jib according to claim 3 wherein all slide pad supports at one end of a section are interconnected by a supporting framework.

5. A jib according to claim 3 wherein said slide pad support is reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted.

6. In a telescopic jib: at least a pair of relatively telescopic jib sections, each of said jib sections comprising a plurality of parallel spaced apart hollow tubular longitudinal members, each of said longitudinal members being of rectangular cross section and comprising inwardly and outwardly facing flat bearing surfaces, and a plurality of slide pad assemblies to facilitate relative telescopic movement and transfer thrust forces between said jib sections, each slide pad assembly comprising a slide pad support of rectangular cross section inserted into and non-rotatably engaged within an end of a longitudinal member of one jib section, a slide pad mounted on said slidepad support and slidably engaged with a flat bearing surface on a longitudinal member of another jib section, and bolt means for securing said slide pad to said slide pad support, each slide pad support being reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted.

7. A jib according to claim 6 wherein each said slide pad assembly includes shim means disposed between said slide pad support and said slide pad.

8. A jib according to claim 6 wherein said slide pad support includes a relieved portion at which said slide pad is mounted.

9. A jib according to claim 8 wherein said slide pad assembly includes shim means disposed between said slide pad and said relieved portion, and including bolt means for securing said slide pad and shim means to said slide pad support.

' 10. In a jib section for a telescopic jib: a plurality of parallel spaced apart hollow tubular longitudinal members, each longitudinal member comprising diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof and having a bore of noncircular cross-sectional configuration, a series of cross braces for joining each adjacent pair of longitudinal members and defining sides of said jib section, slide pad assemblies, each comprising a slide pad support of noncircular cross-sectional configuration inserted into and nonrotatably engaged within an end of a longitudinal member and a flat slide pad mounted parallel to and adjacent the plane of the bearing surface of the member on said slide pad support, and a supporting framework generally within the plane of said braces, connected to and between the slide pad supports in said plurality of slide pad supporting assemblies.

11. A jib section according to claim 10 wherein said plurality of slide pad assemblies comprises a pair.

12. A jib section according to claim 10 wherein said plurality of slide pad assemblies comprises an upper pair and a lower pair and wherein said supporting framework is rectangular.

13. In a jib section for a telescopic jib: four parallel spaced apart hollow tubular longitudinal members, each of said longitudinal members being of rectangular cross section and comprising diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof, a series of cross braces joining each adjacent pair of longitudinal members and defining planar sides of said jib section, a slide pad support inserted into and engaged within an end of each longitudinal member at least at one end of said section, a flat slide pad parallel to and close to the plane of the adjacent bearing surfaces mounted on at least two of said slide pad supports, and a supporting framework connected to and between all of said slide pad supports and disposed generally in the planes of said sides.

14. A jib section according to claim 13 including a slide pad mounted on each of said slide pad supports.

on which it is mounted.

* i i i 

1. In apparatus having a telescopic jib; at least a pair of relatively telescopic jib sections, each section comprising four parallel spaced apart hollow tubular longitudinal members, each longitudinal member in each section having a rectangular cross section and comprising diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof and two flat surfaces to which the ends of cross braces are welded and having a bore of non-circular cross-sectional configuration, cross braces for joining each adjacent pair of longitudinal members and defining four planar sides of said jib sections, each longitudinal member being disposed on its axis so that all surfaces thereof are at a 45* angle with respect to the sides of its jib section, and two inwardly facing slide pad assemblies mounted at the lower front end of one section, two outwardly facing slide pad assemblies mounted at the lower rear end of the other section, and two outwardly facing slide pad assemblies mounted at the upper rear end of said other section, each slide pad assembly comprising a slide pad support of non-circular cross-sectional configuration inserted into and non-rotatably engaged within the bore at an end of one of said longitudinal members and a slide pad having a flat surface mounted on said slide pad support and slidably engaged with a flat bearing surface on a longitudinal member in an adjacent jib section.
 2. A jib according to claim 1 wherein said slide pad support is reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted.
 3. In a telescopic jib: a base section, an intermediate section telescopable within said base section, and a fly section telescopable within said intermediate section; each of said sections comprising four parallel spaced apart hollow tubular longitudinal members, each of said longitudinal members having a rectangular cross section and comprising generally diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof and further comprising two other flat surfaces; a series of angularly disposed tubular cross braces for joining each adjacent pair of longitudinal members in a section and defining sides of said section; said cross braces being welded at each end to one of said other flat surfaces of a longitudinal member; slide pad supports of rectangular cross section inserted into and now rotatably engaged within the ends of the longitudinal members at the front end of said base section, at both ends of said intermediate section, and at the rear end of said fly section; and flat slide pads mounted on the slide pad supports at the lower front end of said base section, at the upper and lower rear end of said intermediate section, at the lower front end of said intermediate section, and at the upper and lower rear end of said fly section, those slide pads at the lower front ends of said base section and said intermediate section being inwardly facing and all other slide pads being outwardly facing.
 4. A jib according to claim 3 wherein all slide pad supports at one end of a section are interconnected by a supporting framework.
 5. A jib according to claim 3 wherein said slide pad support is reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted.
 6. In a telescopic jib: at least a pair of relatively telescopic jib sections, each of said jib sections comprising a plurality of parallel sPaced apart hollow tubular longitudinal members, each of said longitudinal members being of rectangular cross section and comprising inwardly and outwardly facing flat bearing surfaces, and a plurality of slide pad assemblies to facilitate relative telescopic movement and transfer thrust forces between said jib sections, each slide pad assembly comprising a slide pad support of rectangular cross section inserted into and non-rotatably engaged within an end of a longitudinal member of one jib section, a slide pad mounted on said slide pad support and slidably engaged with a flat bearing surface on a longitudinal member of another jib section, and bolt means for securing said slide pad to said slide pad support, each slide pad support being reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted.
 7. A jib according to claim 6 wherein each said slide pad assembly includes shim means disposed between said slide pad support and said slide pad.
 8. A jib according to claim 6 wherein said slide pad support includes a relieved portion at which said slide pad is mounted.
 9. A jib according to claim 8 wherein said slide pad assembly includes shim means disposed between said slide pad and said relieved portion, and including bolt means for securing said slide pad and shim means to said slide pad support.
 10. In a jib section for a telescopic jib: a plurality of parallel spaced apart hollow tubular longitudinal members, each longitudinal member comprising diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof and having a bore of noncircular cross-sectional configuration, a series of cross braces for joining each adjacent pair of longitudinal members and defining sides of said jib section, slide pad assemblies, each comprising a slide pad support of non-circular cross-sectional configuration inserted into and nonrotatably engaged within an end of a longitudinal member and a flat slide pad mounted parallel to and adjacent the plane of the bearing surface of the member on said slide pad support, and a supporting framework generally within the plane of said braces, connected to and between the slide pad supports in said plurality of slide pad supporting assemblies.
 11. A jib section according to claim 10 wherein said plurality of slide pad assemblies comprises a pair.
 12. A jib section according to claim 10 wherein said plurality of slide pad assemblies comprises an upper pair and a lower pair and wherein said supporting framework is rectangular.
 13. In a jib section for a telescopic jib: four parallel spaced apart hollow tubular longitudinal members, each of said longitudinal members being of rectangular cross section and comprising diagonally inwardly and outwardly facing flat bearing surfaces on opposite sides thereof, a series of cross braces joining each adjacent pair of longitudinal members and defining planar sides of said jib section, a slide pad support inserted into and engaged within an end of each longitudinal member at least at one end of said section, a flat slide pad parallel to and close to the plane of the adjacent bearing surfaces mounted on at least two of said slide pad supports, and a supporting framework connected to and between all of said slide pad supports and disposed generally in the planes of said sides.
 14. A jib section according to claim 13 including a slide pad mounted on each of said slide pad supports.
 15. A jib according to claim 13 wherein said slide pad support is reversely mountable within a longitudinal member so that said slide pad mounted thereon can face inwardly or outwardly with respect to a jib section on which it is mounted. 